"I know there will more time of my life spent off the floor than on the floor," says LeBron James, who is already preparing for life off the basketball court by making investments today.

He's not the only one planning ahead.

"Players are now taking more ownership over decision-making when it comes to their investments," says Courtney Brunious, associate director of USC's Sports Business Institute.

Here are some of the start-ups and more established companies in which James and other star athletes are investing their millions.

Andre Iguodala

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Andre Iguodala #9 of the Golden State Warriors

Iguodala's team, the Golden State Warriors, plays just across the bay from San Francisco, and the star forward is taking advantage of his proximity to Silicon Valley.

"We have some great relationships with VCs [venture capitalists] out there, mainly Andreessen Horowitz," Iguodala tells CNBC. "They've kind of taken me under their wing and ... showed me some things in the portfolio and how I can integrate my brand into some of their brands."

Kevin Durant

Durant, another Golden State Warrior, says he's following the example of his teammate Iguodala.

The NBA star has been known to hang out with Silicon Valley's A-list and "is laying the foundation for a tech empire of his own," The New York Times reports.

According to the Times, Durant's portfolio includes investments "in tech companies like Postmates and Acorns, in addition to hotels and restaurants and film and television development." And like Iguodala, he's also an investor in The Players' Tribune.

Stephen Curry

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A third Warrior is taking advantage of the team's ties to Silicon Valley: Two-time MVP Stephen Curry.

Serena Williams

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Serena Williams

As of June 2017, the 23-time Grand Slam tennis champion is backing Daily Harvest, a food start-up that delivers healthy, frozen meals to your home.

"I invest in businesses that operate with sincerity and integrity and deliver a pure and uncompromised product," says Williams in a press release. "I'm excited about Daily Harvest's future as a female-led business and I look forward to helping more people gain access to nutritious meals."

"When I met the Blue Jeans team, I was busy starting my new venture, The Players' Tribune," the former all-star shortstop tells Business Insider. "I was captivated by what Blue Jeans' video could do to amplify the voice of our athletes."

Chris Paul

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Chris Paul #3 of the Los Angeles Clippers drives on Klay Thompson #11 of the Golden State Warriors in Game Four of the Western Conference Quarterfinals during the 2014 NBA Playoffs at ORACLE Arena on April 27, 2014 in Oakland.